The invention disclosed herein relates to thermostat subbases and particularly to subbases using conductive paths cut from a grid of conductive material for interconnections within the subbase rather than individual conductors.
Thermostat subbases are typically mounted on a wall and include terminals for electrical connection of field control wiring from the heating and cooling apparatus. After the control wiring is connected to the terminals, a thermostat is typically mounted on the subbase and electrically interconnected to the subbase. The subbase typically also performs functions such as selecting either heating or cooling apparatus to be controlled by the thermostat. Other typical subbase functions include selecting an operating mode for an air circulating fan or providing light or LED indication of system status.
Numerous electrical terminal connections and the switching functions require that many individual conductive paths are provided in a thermostat subbase. The use of separate conductors and separate switches is a labor intensive approach to this need. Therefore this requirement has lead to various other approaches. One approach is the use of a conductive grid which can be placed on a subbase and then segmented into various conductive portions or paths.
Subbases are known which locate the conductive grid on the back surface of the subbase. Separate conductive terminals are then mechanically attached to the grid and extend through the subbase. These terminals are then used for both field control wiring and thermostat interconnections. Switching can be provided by extending the ends of grid portions through the base and using a switch lever to move a conductive ball across the ends of the grid portions.
Subbases having a back surface grid provide generally satisfactory performance but have certain disadvantages. The use of separate conductive terminals that are mechanically secured to the grid requires the use of screw machine manufactured terminals and individual handling of the terminals resulting in a costly subbase. The present invention eliminates troublesome electrical connections and handling of loose parts in an automated process.
Switching a conductive ball across the rounded ends of grid portions that extend through the subbase generally provides satisfactory operation. It does require accurate alignment of the rounded ends to assure sufficient contact of adjoining ends by the conductive ball.